1. Field of the Invention
The present invention relates to a fastener connected by tape (hereinafter, called as "tape-connected fastener") such as paper-connected nails for use in a nailing machine for building, paper-connected screws for use in a screwing machine for building, or the like. In particular, the present invention relates to a tape-connected fastener for stabilizing the posture of a nail or a screw in nailing or in screwing, respectively.
2. Description of the Related Prior Art
As connected fasteners, plate-like connected nails, connected screws or the like are used. Plate-like connected nails, called as stick nails, are long nails about 65 mm to 90 mm long and connected for use in 2.times.4 building or the like. There are some types of connected nails or connected screws such as a resin-belt-connected fastener, a paper-connected fastener, and wire-connected nails. The resin-belt-connected fastener is connected by penetrating shaft portions of nails or screws into a belt of resin materials, which are reduced in toughness by mixing calcium carbonate into polypropylene. The paper-connected fastener is connected by bonding shaft portions of nails or screws to reinforced paper tape such as kraft paper or the like with thermoplastic resin. The wire-connected nails are connected by spot-welding a wire with longitudinally intermediate portions of shaft portions of nails to thereby hold the nails.
In the above-mentioned fasteners, the resin-belt-connected fastener is regarded as unsuitable for indoor work because a driver of a nailing machine or a screwing machine hits nails or screws so that the resin belt is broken and crushed, and the crushed portions of the resin belt fly in all directions. Similarly, the wire-connected nails also have such a problem that broken portions of the wire fly in all directions. Therefore, the paper-connected fastener is often used because of its smaller amount of waste and its less danger.
Material which is higher in toughness than the resin material of the resin-belt-connected fastener is used for the bonding agent of the thermoplastic resin used in the paper-connected fastener because it is necessary to bond nails or screws firmly. As a result, the paper-connected fastener is inferior, in instantaneous shearing, to the resin-belt-connected fastener while the amount of paper or resin flying in all directions is small upon shearing.
Therefore, as shown in FIG. 7A, when a driver 3 of a nailing machine 2 hits a front nail 5a in a nose 4 to drive paper-connected nails 1, the ductility of the bonding agent prevents paper tape 6 from being sheared instantaneously. Accordingly, the paper tape 6 extends as shown in FIG. 7B so that the nail 5a takes a posture such that the head portion of the nail 5a moves forward as shown in FIG. 7C, while the tip end portion of the nail 5a approaches the next nail 5b. Thus, the paper tape 6 begins to tear from its upper portion toward its lower portion.
This shearing characteristic, in the paper-connected nails 1, causes a tendency that the nail 5 may make an inclined landing, as shown in FIG. 8A. Consequently, there is a case that the nail head is shifted from a position just under the driver 3 so that the nail 5 cannot be driven vertically. In the worst case, the driver 3 may slip from the nail head to get out of place forward to result in failure in nailing, as shown in FIG. 8B, or the nail may be bent in the nose 4 of the nailing machine 2 to block the nose 4. In addition, such a failure is apt to arise more often especially when a short nail is driven or when a nail is driven into material which is high in hardness and large in driving load.
The above-mentioned phenomenon appears in the same way also in paper-connected screws in which a number of screws are connected by the paper tape. That is, in some cases, a screw in a nose of a screwing machine has a collision with the circumference of a screw chuck provided in the forward end of the nose portion of the screwing machine, so that the screw is not introduced into the screw chuck, but it blocks the nose.
Therefore, there arises a technical problem how to stabilize the posture of a nail or a screw at the time of driving the nail or screw of paper-connected nails or paper-connected screws and how to eliminate the failure in work.